Geneesmiddelenbiotransformatie: Overzicht

Drugs are special xenobiotics that are mostly lipophilic and nonionized. This allows the drug to pass through the lipid bilayers to reach target receptors in the cell.

Lipophilic drugs, however, often exhibit limited renal excretion capacity as they are  reabsorbed rapidly from the glomerular filtrate into the blood. Their accumulation in the body prolongs drug action and precipitates toxic reactions.

To prevent this, drugs can be biotransformed into hydrophilic derivatives, which allows their enhanced elimination through urine.

Although several body tissues can metabolize drugs, the liver is the primary site for biotransformation.

Drug biotransformation involves two primary reactions that occur sequentially and are catalyzed by specific cellular enzymes.

Phase I reactions are catabolic and involve functionalization, whereas phase II reactions are anabolic and involve conjugation.

The process of metabolism often terminates the drug's biological activity, but in prodrugs, enhanced activity is attained.